diff options
| -rw-r--r-- | EdkModulePkg/Core/DxeIplX64Peim/DxeLoadX64.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/EdkModulePkg/Core/DxeIplX64Peim/DxeLoadX64.c b/EdkModulePkg/Core/DxeIplX64Peim/DxeLoadX64.c index d011858cb9..7b293ef0c2 100644 --- a/EdkModulePkg/Core/DxeIplX64Peim/DxeLoadX64.c +++ b/EdkModulePkg/Core/DxeIplX64Peim/DxeLoadX64.c @@ -260,10 +260,14 @@ Returns: //
// Compute the top of the stack we were allocated. Pre-allocate a 32 bytes
- // for safety (PpisNeededByDxe and DxeCore).
+ // for x64 calling convention.
//
- TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT;
- TopOfStack = (EFI_PHYSICAL_ADDRESS) ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
+ // The first four parameters to a function are passed in rcx, rdx, r8 and r9.
+ // Any further parameters are pushed on the stack. Furthermore, space (4 * 8bytes) for the
+ // register parameters is reserved on the stack, in case the called function
+ // wants to spill them; this is important if the function is variadic.
+ //
+ TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - 32;
//
// Add architecture-specifc HOBs (including the BspStore HOB)
|